papers

Publications (14)

cs.NE2025

CatCMA : Stochastic Optimization for Mixed-Category Problems

Ryoki Hamano, Shota Saito, Masahiro Nomura +2

Black-box optimization problems often require simultaneously optimizing different types of variables, such as continuous, integer, and categorical variables. Unlike integer variabl…

cs.LG2026

On the Generalization Bounds of Symbolic Regression with Genetic Programming

Masahiro Nomura, Ryoki Hamano, Isao Ono

Symbolic regression (SR) with genetic programming (GP) aims to discover interpretable mathematical expressions directly from data. Despite its strong empirical success, the theoret…

cs.NE2026

Convergence Analysis of Evolution Strategies for Mixed-Integer Optimization

Ryoki Hamano, Kento Uchida, Shinichi Shirakawa

Mixed-integer extensions of evolution strategies (ES) that discretize selected coordinates of sampled continuous vectors often impose a lower bound on the standard deviation of int…

cs.NE2023

CMA-ES with Margin: Lower-Bounding Marginal Probability for Mixed-Integer Black-Box Optimization

Ryoki Hamano, Shota Saito, Masahiro Nomura +1

This study targets the mixed-integer black-box optimization (MI-BBO) problem where continuous and integer variables should be optimized simultaneously. The CMA-ES, our focus in thi…

math.OC2024

CMA-ES for Discrete and Mixed-Variable Optimization on Sets of Points

Kento Uchida, Ryoki Hamano, Masahiro Nomura +2

Discrete and mixed-variable optimization problems have appeared in several real-world applications. Most of the research on mixed-variable optimization considers a mixture of integ…

cs.NE2026

Adaptive Stochastic Natural Gradient Method for Safe Optimization on Binary Space

Kento Uchida, Ryoki Hamano, Masahiro Nomura +1

Optimization problems in real-world applications across the medical and engineering domains often involve potential risks when evaluating candidate solutions. Safe optimization aim…

cs.NE2026

Diversified Residual Symbolic Regression

Koki Ikeda, Masahiro Nomura, Ryoki Hamano

Symbolic regression (SR) aims to discover explicit mathematical expressions that explain observed data and is widely used in domains where interpretability is essential. Because in…

cs.NE2024

Natural Gradient Interpretation of Rank-One Update in CMA-ES

Ryoki Hamano, Shinichi Shirakawa, Masahiro Nomura

The covariance matrix adaptation evolution strategy (CMA-ES) is a stochastic search algorithm using a multivariate normal distribution for continuous black-box optimization. In add…

cs.NE2026

CatCMA with Margin for Single- and Multi-Objective Mixed-Variable Black-Box Optimization

Ryoki Hamano, Masahiro Nomura, Shota Saito +2

This study focuses on mixed-variable black-box optimization (MV-BBO), addressing continuous, integer, and categorical variables. Many real-world MV-BBO problems involve dependencie…

cs.NE2026

cmaes: A Simple yet Practical Python Library for CMA-ES

Masahiro Nomura, Masashi Shibata, Ryoki Hamano

The covariance matrix adaptation evolution strategy (CMA-ES) has been highly effective in black-box continuous optimization, as demonstrated by its success in both benchmark proble…

cs.NE2024

Tail Bounds on the Runtime of Categorical Compact Genetic Algorithm

Ryoki Hamano, Kento Uchida, Shinichi Shirakawa +2

The majority of theoretical analyses of evolutionary algorithms in the discrete domain focus on binary optimization algorithms, even though black-box optimization on the categorica…

cs.NE2023

(1+1)-CMA-ES with Margin for Discrete and Mixed-Integer Problems

Yohei Watanabe, Kento Uchida, Ryoki Hamano +3

The covariance matrix adaptation evolution strategy (CMA-ES) is an efficient continuous black-box optimization method. The CMA-ES possesses many attractive features, including inva…

cs.NE2024

CMA-ES for Safe Optimization

Kento Uchida, Ryoki Hamano, Masahiro Nomura +2

In several real-world applications in medical and control engineering, there are unsafe solutions whose evaluations involve inherent risk. This optimization setting is known as saf…

cs.NE2024

Marginal Probability-Based Integer Handling for CMA-ES Tackling Single-and Multi-Objective Mixed-Integer Black-Box Optimization

Ryoki Hamano, Shota Saito, Masahiro Nomura +1

This study targets the mixed-integer black-box optimization (MI-BBO) problem where continuous and integer variables should be optimized simultaneously. The CMA-ES, our focus in thi…